[URL="http://api.tweetmeme.com/share?url=http://espn.go.com/nfl/trainingcamp12/story/_/id/8266630/cedric-benson-joins-green-bay-packers&service=bit.ly&source=espn"][IMG]http://api.tweetmeme.com/imagebutton.gif?url=http://espn.go.com/nfl/trainingcamp12/story/_/id/8266630/cedric-benson-joins-green-bay-packers[/IMG][/URL]Cedric Benson knows there's an expiration date stamped on any NFL player and that it seems to come up sooner for running backs than anyone else.